<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta http-equiv="X-UA-Compatible" content="IE=edge" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>Document</title>
		<link rel="stylesheet" href="./grid.css" />
		<style>
			[class*="col-"] {
				padding-top: 10px;
				padding-bottom: 10px;
				border: 1px solid gray;
			}
		</style>
	</head>
	<body>
		<div class="container">
			<div class="row">
				<div class="col-1">1</div>
				<div class="col-1">2</div>
				<div class="col-1">3</div>
				<div class="col-1">4</div>
				<div class="col-1">5</div>
				<div class="col-1">6</div>
				<div class="col-1">7</div>
				<div class="col-1">8</div>
				<div class="col-1">9</div>
				<div class="col-1">10</div>
				<div class="col-1">11</div>
				<div class="col-1">12</div>
			</div>
			<div class="row">
				<div class="col-4">
					<!-- 嵌套 -->
					<div class="row">
						<div class="col-3">1</div>
						<div class="col-3">2</div>
						<div class="col-3">3</div>
						<div class="col-3">3</div>
					</div>
				</div>
				<div class="col-4"></div>
				<div class="col-4"></div>
			</div>
		</div>
	</body>
</html>
